1. Field of the Invention
The invention relates generally to methods for diagnosing disease and particularly to methods for diagnosing degenerative joint disease.
2. Description of Related Art
Methods for diagnosing joint related conditions are known in the art. WO28049225A1 discloses methods for prognosing osteoarthritis by determining the cellular localization of pituitary homeobox transcription factor 1 (pitx-1) repressor protein or complex, e.g., prohibitin or prohibitone in a sample, e.g., articular chondrocytes sample. US20070248986A1 discloses methods for predicting the likelihood of developing rheumatoid arthritis for individuals with recent-onset undifferentiated arthritis by determining a set of clinical parameter values and a predicted risk for developing rheumatoid arthritis by correlating the parameter values with predefined risk values associated with ranges of parameter values, e.g., serum levels of C-reactive protein, Rheumatoid factors, anti-CCP antibodies, age, gender, localization of the joint complaints, length of morning stiffness, and number of tender and/or swollen joints. U.S. Pat. No. 7,005,274 discloses diagnostic methods for early detection of a risk for developing an arthritic disorder in humans and screening assays for therapeutic agents useful in the treatment of arthritic disorders by comparing the levels of one or more indicators of altered mitochondrial function, e.g., enzymes such as mitochondrial enzymes, ATP biosynthesis factors, mitochondrial mass, mitochondrial number, mitochondrial DNA content, cellular responses to elevated intracellular calcium and to apoptogens, and free radical production. US20040242987A1 discloses methods for predicting bone or articular disease affecting musculoskeletal system (e.g., osteoporosis) by obtaining micro and macro-structural or biomechanical parameters obtained from images of a joint and analyzing at least two of the parameters, e.g., macro anatomical parameters and biomechanical parameters. Other known methods include physical examination, plain film radiography, computed axial tomography (CAT) scans, magnetic resonance imaging (MRI) scans, contrast radiography, and arthroscopy.
Diagnosing joint related conditions such as degenerative joint disease in animals using physical examination and plain film radiography is common. In particular, these methods are the primary tools for diagnosing osteoarthritis in various animals such as dogs. However, affected animals often do not exhibit overt lameness or other symptoms indicating degenerative joint disease. Unfortunately, this means that observable clinical signs are insufficient to support a presumptive diagnosis of degenerative joint disease, e.g., osteoarthritis. Further, plain film radiography, while it is the most frequently used screening technology, reveals bony changes but often does not demonstrate changes in soft tissues such as the joint capsule, thus complicating routine diagnosis. Similarly, CAT and MRI scans are expensive and often not widely available. Contrast radiography and arthroscopy add a degree of invasiveness. In some animals such as dogs, these additional modalities always require some form of restraint such as anesthesia, thus adding cost, complexity, and risk. Given these limitations to known methods, degenerative joint disease often goes undiagnosed. There is, therefore, a need for new methods for diagnosing degenerative joint disease in animals.